Greenplum 7 新特性整理

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新特性总结

Greenplum 7 新特性整理

快速拥有GPDB 7和gpcc 7环境

参考:https://www.xmmup.com/zaidockerzhongkuaisutiyangreenplum-7-0-0.html

此docker包括1个master,1个standby master,2个segment,2个mirror实例;还包括gpcc 7.0.0

http://192.168.8.8/28080

gpmon/lhr

Greenplum 7 新特性整理

重要的新特性

内核

Greenplum 7的内核从9.4.26升级到了12.12,其性能、功能均领先于Greenplum 6

自动启用vacuuum

缺省打开了autovacuum,会自动对系统表进行VACUUM和ANALYZE操作,并对用户表进行ANALYZE操作。

INSERT,UPDATE和DELETE影响的数据量大于下面的计算结果时,会自动对操作的表进行ANALYZE操作:

Automatic Vacuum is now enabled by default for all databases, which automatically performs VACUUM and ANALYZE operations against all catalog tables, as well as runs ANALYZE for all users tables in those databases.

参数含义参考: https://docs.vmware.com/en/VMware-Greenplum/7/greenplum-database/ref_guide-config_params-guc-list.html#autovacuum

示例:

支持仅索引扫描和覆盖索引

增加了对覆盖索引(covering index)的支持。覆盖索引允许用户使用INCLUDE 子句将额外的列添加到索引中,对于执行索引 (index-only)扫描非常有用,特别是对于那些不能被B-tree所索引的数据类型。 Greenplum 查询优化器部分支持索引扫描和覆盖索引。

注意:不能使用GitHub上的开源版本,否则不能使用仅索引扫描和覆盖索引!!!

Index-only scans can answer queries from an index alone without accessing the table’s heap, which significantly improves query performance. In addition, covering indexes allow you to add additional columns to an index using the INCLUDE clause, in order to make the use of index-only scans more effective. See Understanding Index-Only Scans and Covering Indexes for more details.

支持Index only的索引扫描,并支持CREATE INDEX的INCLUDE子句,允许在索引查询时不再回表,从而提升索引查询的性能。

测试环境:

视频:https://www.youtube.com/watch?v=J7_xLoq3E20&t=1383s

引入监控视图可以监控长运行的操作

引入了pg_stat_progress_vacuum/copy/create_index等进度视图。

Greenplum Database can report the progress of ANALYZE, CLUSTER, COPY, CREATE INDEX, REINDEX, and VACUUM commands during command execution. Greenplum can also report the progress of a running base backup (initiated during gprecoverseg -F) command invocation, allowing you to monitor the progress of these possibly long-running operations.

参考:

https://docs.vmware.com/en/VMware-Greenplum/7/greenplum-database/admin_guide-managing-progress_reporting.html

https://greenplum.org/progress-reporting-views-in-greenplum-7/

https://greenplum.org/partition-in-greenplum-7-recursion-and-inheritance/

新增pg_backend_memory_contexts的系统视图

新增了一个名为pg_backend_memory_contexts的系统视图,可以查看后台的内存使用情况。

增加列不再需要重写表

Greenplum Database no longer rewrites the table when a column is added to a table (ALTER TABLE ... ADD COLUMN ...).

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